Effects of nanoplastic exposure on the immunity and metabolism of red crayfish (Cherax quadricarinatus) based on high-throughput sequencing

Previous studies have shown that nanoplastics (NPs) are harmful pollutants that threaten aquatic organisms and ecosystems, however, less research has been conducted on the hazards of NPs for aquaculture animals. In this study, Cherax quadricarinatus was used as an experimental model to evaluate the possible effects of three concentrations (25, 250 and 2500 μg/L) of NPs on red crayfish. The toxicological effects of NPs on this species were investigated based on transcriptomics and microbiome. A total of 67,668 genes were obtained from the transcriptome. The annotation rate of the four major libraries (Nr, KEGG, KOG, Swissprot) was 40.17 %, and the functions of differential genes were mainly related to antioxidant activity, metabolism and immune processes. During the experiment, the activities of superoxide dismutase (SOD) and catalase (CAT) in the high concentration group were significantly decreased, while the concentration of malondialdehyde (MDA) increased after nanoplastics (NPs) exposure, and SOD1, Jafrac1 were significantly reduced at high concentrations. expression is inhibited. The immune genes LYZ and PPO2 were highly expressed at low concentrations and suppressed at high concentrations. After 14 days of exposure to NPs, significant changes in gut microbiota were observed, such as decreased abundances of Actinobacteria, Bacteroidetes, and Firmicutes. NPs compromise host health by inducing changes in microbial communities and the production of beneficial bacterial metabolites. Overall, these results suggest that NPs affect immune-related gene expression and antioxidant enzyme activity in red crayfish and cause redox imbalance in the body, altering the composition and diversity of the gut microbiota.